The present invention is directed to an appliance for winding a cable evenly over the full length of a drum in cases where the fleet angle exceeds approximately 4.degree. or where the distance of a lead or fixed lead sheave 2 in front of the drum 3 is shorter than approximately 7 times the drum length, as shown in FIG. 1, where X is the drum length and Y equals the distance between the fixed lead sheave and the drum.
Conventional spooling arrangements adjust the wire position opposite the drum by means of mechanical drives; in the present invention, however, the appliance of cable is directed solely by the previously laid-on drum winding of cable, and all other influences are eliminated.
The spooling of cable on a drum is fulfilled for the present invention if, in any position of the spooling gear between drum 3 and fixed lead sheave 2, the total length of wire between the meeting points on drum and sheave remains constant, as shown in FIG. 2, where a+c=a'+c'. a and a' are the length of cable between fixed lead sheave 2 and movable lead sheave 1. c and c' are the length of cable between drum 3 and movable lead sheave 1. a and c illustrate a different position of the wire on the movable lead sheave 1 as compared to a'+c'.
The taut cable always seeks the shortest distance between those two points (the fixed lead sheave 2 and the drum 3), and, if this does not exist, there will be no preference for any position at all. The spooler, apart from moving along the drum, must therefore also travel along a path such that the distance a+c of the cable remains constant. This path lies in a plane perpendicular to the cable and proves to be almost circular, with a radius depending on the distance between the fixed lead sheave and the drum and the angle of the cable between the spooler fixed lead sheave 2 and the drum 3.
Because the force generated by the cable on the spooler should not influence the movement of the cable, it is necessary that the direction of this force is perpendicular to the path of the cable and should not cause interfering resistances along the path.
A well-known device fulfilling these conditions, as shown in FIGS. 1 and 2, produces the required path for the cable by means of a movable lead sheave 1 rotating and translating along a shaft 50 which, in turn, by means of a crank shaft 52 securely placed at one end to shaft 50 and at the other end to movable lead sheave 1, makes an oscillating movement along the path of arrow 54 in front of the drum 3, the path of travel of the cable being governed by the length and angle of the crank shaft 52.
The use of swiveling bearings for the mounting of the movable lead sheave 1 on crank shaft 52 restricts the length of the crank shaft 52 in comparison with the drum length so that Y is greater than 2.4X.
For long length X drums and high loads, special high tensile materials are required. In addition, complicated dismounting and provisions are necessary for maintaining the proper position of the movable lead sheave 1 when the cable slackens.